Steam air-pump



No Model.)

A. P. MASSBY.

STEAM AIR PUMP. No. 428,120. Patented May 20, 1890.

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UNITED STATES PATENT OFFICE.

ALBERT MASSEY, OF VATERTOIVN, NEV YORK.

ySTEAM AIR-PUM P.

SPECIFICATION forming part of Letters Patent No. 428,120, dated May 20,1890.

Application filed February 14, 1890. Serial No. 340,406. (No model.)

To a/ZZ whom, t may concern.-

Be it known that I, ALBERT P. MASSEY, a citizen of the United States,residing in the city of Watertown, in the county of Jefferson and Stateof New York, haveinvented certain new and useful Improvements in SteamAir- Pumps, of which the following, taken in connection with'theaccompanying drawings, is a specification.

The object of my invention is to produce a duplex steam air-pump thatwill work with greater economy of steam than those at present in use. Icompress the contents of two air-cylinders of unequal size into thesmaller cylinder by means of one steam-piston, and then compress thecontents of the smaller cylinder still further by means of anothersteampiston. l

Figure 1 is a sectional View of the complete apparatus. Fig. 2 is a viewof the upper head of the steam-cylinders. Fig. 8 is a view of the upperhead of the air-cylinders.

The steam-valves are actuated by what is known as the duplex system.

In the drawings, 1 and 2 are steam-cylinders.

3 and 4 are air-cylinders.

5 and 6 are valves for controlling the action of the steam-pistons.

7 and 8 are valve-stems.

9 and 10 are valves admitting air alternately to the largerair-cylinder.

11 and 12 are valves between the two aircylinders.

13 and 14 are valves between the smaller air-cylinder and the reservoirconnectedvto pump at 15.

Steam is -admitted to the steam-chests 16 and 17 through port 18, and isexhausted through port 19.

The valve-stems 7 and S are actuated by the plates 20, which are securedto the pistons and come incontact with the tappets on the valve-stem ina manner described in Patent No, 115,668, issued to George `Westinghouse, .lune 6, 1871.

The cycle of operations is as follows: In the position shown theair-piston in cylinder4 has completed its downward stroke and compressedits contents through valve 12 into cylinder The plate 2O on steam-piston21 has moved valve 6 to its lowest position. This admits steam throughport 23 to upper side of piston 22, and will cause the piston to descendand expel the partially-compressed air in cylinder 3 through valve 14and passage 15 into the reservoir. Meanwhile the cylinder 4 has becomefilled above the piston with air at atmospheric pressure through valve9, and the cylinder 3 will be filled with air at atmospheric pressurethrough valves 9 and 11, both of which open inward and are seated bygravity. Vhen piston 22 reaches the end of its downward stroke, theplate 2O strikes the tappet on valve-stem 7 and moves valve 5 to itslowest position, thus uncovering port 24 and admitting steam throughport 24 25 26 to the lower side of piston 21, thus causing piston 21 torise and compress the air which is in cylinder 4 through valve 11 intoupper part of cylinder 3. J ust as piston 21 completes its stroke itsplate 2O strikes the tappet on valve-stein 8 and moves -valve 6 to itshighest position, uncovering port 27` and admitting steam through 27 2S29 to the lower side of piston 22, causing the piston to rise and expelthe partially-compressed air in cylinder 3 through valve 13 into passage15,and thence into the reservoir. Vhile the pistons were compressing theair above them into the reservoir, the air-cylinder below the pistonswould fill with air at atmospheric pressure through valves 10 and12,-ready for another cycle of operation.

' In a single-cylinder air-pump the resistance in the air-cylindervaries each stroke from naught to the extreme pressure in thereservoir-say one hundred. pounds. The steampiston must therefore havesufiicient area to produce this final pressure and expel the air intothe reservoir. In other words, the steampiston must be as large as theair-piston in ordinary locomotive practice, where the usual pressure inthe boiler is from one hundred and twenty pounds upward.

In my invention the extreme resistance to the leading piston 21 is tocompress the contents of the two air-cylinders into one. The arca of theleading air-cylinder 4 can therefore be as much greater than thesteamcylinder as the steam-pressure exceeds the final pressure in theair-cylinder with due allowance for friction, &c. In practice the areaof cylinder 4 may be twice that of cyl- IOO inder 2. The other cylinders1 and 3 are the same size as 2. It follows, therefore1 that the linalresistance in cylinder 1 would be the pressure resul ting fromcompressing three volumes of air into one volume or thirty pounds aboveatmospheric pressure. A steamcylinder of one-third the area wouldtherefore be ample with steam at one hundred and twenty pounds; but theratio of two to one serves for illustration. Ihenthe Cylinder 3 isfilled with air at thirty pounds pressure, the resistance each strokewill vary from thirty pounds to one hundred pounds, and a steam-pistonof the same area will be required to expel the air into vthe reservoir.Thus it may he seen that two cylinders full or Volumes of steam atboiler-pressure will deliver three volumes of air into the reservoir,whereas in a single-cylinder air-pump two Volumes of steam atboiler-pressure would deliverbut two volumes of air into the reservoir.

As I claim novel features in both the cngine and the pump, I have made aseparate application for those pertaining' to the pump, which was filedSeptember 21, 1889, Serial No. 324,619.

, lVhat I claim as new, and desire to secure by Letters Patent, is-

In a duplex steam air-pump, the cylinders 1 and i and pistons 22 and 21,each connected to a piston in an air-cylimler, in combination withValve-stems 7 and S, tappets 20, and valves and G, with portscommunicating with each end of the opposite cylinder, substantially asset forth.

In testimony whereof I have signed my name lo this specification, in thepresence of two subscribing witnesses,on this 10th day of February, A.I). 1890.

ALBERT I. MASSEY.

Witnesses:

HENRY W. BOYER, MICHAEL J. MoRKIN.

